diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst
index d36955f..8fa6952 100644
--- a/Doc/library/warnings.rst
+++ b/Doc/library/warnings.rst
@@ -204,7 +204,7 @@
         fxn()
         # Verify some things
         assert len(w) == 1
-        assert isinstance(w[-1].category, DeprecationWarning)
+        assert issubclass(w[-1].category, DeprecationWarning)
         assert "deprecated" in str(w[-1].message)
 
 One can also cause all warnings to be exceptions by using ``error`` instead of